Computing the noncommutative inner rank by means of operator-valued free probability theory
arXiv:2308.03667 · doi:10.1007/s10208-024-09684-5
Abstract
We address the noncommutative version of the Edmonds' problem, which asks to determine the inner rank of a matrix in noncommuting variables. We provide an algorithm for the calculation of this inner rank by relating the problem with the distribution of a basic object in free probability theory, namely operator-valued semicircular elements. We have to solve a matrix-valued quadratic equation, for which we provide precise analytical and numerical control on the fixed point algorithm for solving the equation. Numerical examples show the efficiency of the algorithm.
In the second version we have not only improved the presentation of the results, but we supply in addition now actually also a certificate for the termination of our algorithm (this relies on recent theoretical results in the paper arxiv.org/abs/2406.15922)